
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author moustafa
 */
public class MFilter implements Filter{

    public void init(FilterConfig filterConfig) throws ServletException {
        //throw new UnsupportedOperationException("Not supported yet.");
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        if(((HttpServletRequest)request).getMethod().equalsIgnoreCase("post") && request.getParameter("username").startsWith("M")){
            HttpSession session = ((HttpServletRequest)request).getSession();
            session.setAttribute("error", "Username Starts with 'M'");
            ((HttpServletResponse)response).sendRedirect("index.jsp");
        }else{
            chain.doFilter(request, response);
        }
    }

    public void destroy() {
        //throw new UnsupportedOperationException("Not supported yet.");
    }

}
